1. Field of the Invention
This application relates to apparatus for the detection and analysis of small particles in fluids and, in particular, to apparatus of this type including circuitry for the storage and processing of signals representing the detected particles.
The apparatus of this invention is particularly useful in the monitoring of industrial processes and the identification of various particles without the intervention of human operators. Typical applications are in oceanography or industrial applications such as milk analysis.
2. Prior Art
It is known to use a Coulter detector to establish particle size by having the particles carried in a conductive liquid. When a particle encounters a restriction in its flow path it displaces a significant amount of the conductive liquid with a resulting change in conductivity giving an indication of particle size. It is also known to detect and analyse small particles and fluids by causing the particles to traverse singly across the sensing zone irradiated by coherent light from a laser. As shown in U.S. Pat. No. 4,596,464 issued to Hoffman on June 24, 1986 scattered light is detected and analysed to give information as to the characteristics of a particle. The particles may also fluoresce in the sensing zone and the resulting fluorescence is similarly detected and analysed to give information about a particle. This is shown in U.S. Pat. No. 4,475,236 issued to Hoffman on Oct. 2, 1984. If the particles are not themselves fluorescent then an appropriate dye may be added to the sample to produce fluorescence.